The two lower ones are Singer 20. It's an introductory sewing machine geared towards girls. Makes a chain stitch and is pretty simple, gets them ready to graduate to the regular machine. The left one has a motor, the right one is hand operated. I think that top one looks like an old Wilcox and Gibbs, but I never worked on them when I was in the shop-they were just too far and few for me.
Thanks, I thought the top one was a W & G but have never seen one with a motor.